The present invention relates to the contactless comminution of concrements in the body of a living being particularly to the destruction and disintegration of kidney stones in human beings. More particularly the invention relates to equipment of the aforementioned type having a spherical-calotte shaped metal membrane the outwardly curved surfaces of which being juxtaposed to at least one coil but separated therefrom by means of an electrical insulation, and the concavely curved inwardly oriented surface is in contact with an acoustic transmission medium such as a liquid; the coil is energizable by means of electric currents to cause repulsion of the metal membrane so that as a consequence a shock wave is transmitted into the transmission medium and propagates towards the concrement whereby on account of the focusing action of the curvature of the membrane shock wave energy is concentrated into the concrement.
Generally speaking a device of the type to which the invention pertains is shown in my German printed patent application No. 33 12 014. The device disclosed in this application has particular advantages and constitutes a certain progression over an earlier state of the art for contactfree comminution of concrements using underwater sparks or ultrasonic generation. This particular printed patent application describes in detail the earlier state of the art. The particular device suggested by this German patent application has the advantage of simplified construction, a high use life, a high degree of reliability and particularly it excludes certain risks for the general state of health of the patient. Moreover the device disclosed in this application permits avoiding utilization of liquid bath into which the patient has to be submerged and is easier adjustable as compared with the prior art structures and offers more reliably reproducible results.
As far as particulars are concerned printed patent application No. 33 12 014 discloses a conductor arrangement having inductive properties and includes a spirally shaped coil or a coil wound under utilization of a ribbon conductor. This coil configuration has also the shape of a spherical calotte. Upon feeding a current pulse into the coil, e.g. through discharge of a capacitor and connecting it in series with a spark gap opposing currents are induced in a metal membrane being separated from the coil through a thin electrically insulated layer which opposing currents cause in fact a repulsion of the membrane. As an alternative source for electric current a high power generator could be used to feed a current pulse into the coil with the same result as far as membrane action is concerned. Since the membrane is in contact with the transmission medium shock waves are produced and emitted, and on account of the spherical-calotte shaped configuration of the membrane these shock waves are in fact focused e.g. into a kidney stone.